Effects of eugenol, α-terpineol, terpin-4-ol, and methyl eugenol on consumption of alfalfa pellets by sheep

Many secondary compounds are typically present in unpalatable shrubs on arid and semi-arid rangelands. However, the relationship between intake by livestock and concentration of individual chemicals has been examined for very few of these compounds. Four experiments were conducted to examine effects of individual volatile compounds on intake of alfalfa pellets by lambs. Forty-five lambs (9 lambs/treatment) were individually fed alfalfa pellets with eugenol, α-terpineol, terpin-4-ol, or methyl eugenol applied at one of five concentrations. Treatments were multiples (0, 0.5, 1, 2, and 10×) of the concentration (×) of each compound on the leaf surface of Flourensia cernua. Treatment solutions were sprayed on alfalfa pellets (0.64 kg/lamb/d, dry matter basis), and intake was measured during a 20-min interval for five days. A day effect (P < 0.001 for both linear and quadratic contrasts) was detected in all four experiments, but no day × treatment interactions were observed (P > 0.05). No treatment effects were observed (P > 0.05) for any of the chemicals tested; thus, eugenol, α-terpineol, terpin-4-ol, and methyl eugenol were not related to intake of alfalfa pellets by lambs under the conditions of this study.